Attractor Reconstruction for Quantifying the Arterial Pulse Wave Morphology During Device-Guided Slow Breathing

Figures

• 

  Figure 1. Attractor reconstruction using delay coordinates. (a) 60 s sample of pulse waveform data; (b) reconstructed attractor in the three dimensional phase space; (c) projection of the attractor onto a plane orthogonal to the vector (1, 1, 1); and (d) density plot of the two dimensional attractor.

• 

  Figure 2. Attractor measurements.

• 

  Figure 3. Different shapes of the attractors. (a) Triangular attractor; (b) bent attractor; and (c) attractor with overlapping arms.

• 

  Figure 4. (a) Matrix representation of the evolution of the attractor shapes. (b) Boxplot of the percentage of triangular attractors at baseline, end of guided breathing, and end of cooling phase.

• 

  Figure 5. (a), (c) Evolution of the average height h and the average ratio b/a of the attractors during the recording. (b), (d) Boxplots of the average height h and the average ratio b/a of the attractors at baseline, end of guided breathing, and end of cooling phase. The stars indicate the level of significance, where one star means p < 0.05 and three stars mean p < 0.001.

• 

  Figure 6. Artificially generated signals and corresponding attractors to illustrate the influence of crest time/τ. (a) Signal with crest time/τ = 1; (b) triangular attractor in the (v, w) plane; (c) signal with crest time/τ < 1; and (d) bent attractor in the (v, w) plane.

• 

  Figure 7. Pulse wave and corresponding attractor to illustrate the influence of curvature changes. (a) Signal with a small dicrotic wave and crest time/τ < 1; (b) bent attractor with a slightly negative angle of rotation θ; (c) signal with a distinct dicrotic wave and crest time/τ close to 1; and (d) attractor with overlapping sides.

• 

  Figure 8. Difference of heart rate (HR) from baseline for all patients as function over time, smoothed using a 100 s moving average, shown as mean value with 95% confidence interval.